Collaborative Research on the Impact of Permafrost Degradation on Carbon and Water in Boreal Ecosystems
Jennifer Harden, Qianlai Zhuang, Rob Striegl, Yuri Shur, M. Torre Jorgenson
Jon O’Donnell (UAF/USGS, now NPS), Kim Wickland (USGS), Josh Koch (USGS), Kristen Manies (USGS), Stephanie Ewing (Montana State)
NSF Division of Earth Sciences EAR-0630249 USGS Climate, Research and Development Program for Climate and Landuse Change
To understand the impacts of permafrost degradation (thaw) on ecosystem carbon and water cycling, which is critical to the management of habitats and fires on federal lands.
Results to date
The chronosequence approach was used to compare C stocks within four landscapes: 1) rocky uplands, 2) silty uplands on ice-rich loess, 3) gravelly-sandy lowlands, and 4) peaty-silty lowlands on ice-rich peat deposits. This approach found that permafrost thaw has led to the reorganization of vegetation, water storage and flow paths, and patterns in soil organic C accumulation. However, these changes occur over different timescales among these different landscapes (Jorgenson et al., 2013)
Responses of soil C and water to thaw vary greatly. In uplands, C losses to fire were followed by C sequestration by soil as permafrost recovered (O'Donnell et al., 2011), whereas in lowlands, thermokarst was followed by C losses to decomposition (O'Donnell et al., 2012).
Permafrost thawing in Alaska is typically triggered by fire in north-facing slopes and well drained uplands and by thermokarst in low-lying peatlands and wetlands (read more here: Jorgenson et al., 2010)